Real quick for those that are new to this, like me, I just learned this 10 minutes ago so I'm spreading the knowledge.
- On your Steemit account, go to My wallet
- In your wallet, click on the Permissions section
- On the first row( Posting), over to the right, click the "show private key" tab
- Copy the link that shows, it should start with the number 5
- After you copy it, go to your Dtube login screen
- Type in your Steemit username, then Paste the private posting key.
- Press login
And that's it. Same process for DSound. Hope this helps